Asio实现的实用echo server

关于echo的简单server，几乎多得发指，但大部分都没有提供类似粘包，定时器，安全退出等开发中的常用机制，换句话说，为了echo而echo，借鉴价值大打折扣，毕竟我们平时的工作不可能这么简单。这几天研究了下asio，感觉不错，boost接纳asio后，在服务器开发领域是不是该得到重视呢:)，还是贴代码吧，有注释

 

// asio.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"//禁止boost自动链接静态库#define BOOST_ALL_DYN_LINK#include <cstdlib>#include <iostream>#include <boost/bind.hpp>#include <boost/asio.hpp>#include <boost/lexical_cast.hpp>using boost::asio::ip::tcp;class session{public: session(boost::asio::io_service& io_service) : socket_(io_service), timer_(io_service), exit_flag_(false) { std::cout << "session born/n"; } ~session() { std::cout << "session destroy/n"; } tcp::socket& socket() { return socket_; } void start() {//async_receive,async_read_some /* socket_.async_receive(boost::asio::buffer(data_, max_length), boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); */ //读到4个字节才返回，可以和上面注释的sync_receive比较 boost::asio::async_read(socket_, boost::asio::buffer(data_, 4), boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred )); size_t cancelcnt = timer_.expires_from_now(boost::posix_time::seconds(10)); //@return The number of asynchronous operations that were cancelled;第一次启动定时器 std::cout << "timer canceled count is = " << cancelcnt << std::endl; timer_.async_wait(boost::bind(&session::handle_timeout,this, boost::asio::placeholders::error)); }protected: void handle_read(const boost::system::error_code& error, size_t bytes_transferred) {//可以考虑复杂应用，如:如何集成数据库操作等 if (!error) { if (bytes_transferred < header_lenght) {//处理正常退出 std::cout << "need close/n"; this->handle_exit(); delete this; return; } else if (bytes_transferred == header_lenght)//header { data_[bytes_transferred] = '/0'; std::cout << "packet len = " << data_ << std::endl; int bodylen = boost::lexical_cast<int>(data_); boost::asio::async_read(socket_, boost::asio::buffer(data_,bodylen), boost::bind(&session::handle_read,this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); return; } else {//读到了bodylen长度才返回，如果由于网络原因等导致长时间没有读全，则上面的定时器会做超时处理 if (bytes_transferred < max_length) { data_[bytes_transferred] = '/0'; } std::cout << data_ << std::endl; boost::asio::async_write(socket_, boost::asio::buffer(data_, bytes_transferred), boost::bind(&session::handle_write, this, boost::asio::placeholders::error)); // size_t cancelcnt = timer_.expires_from_now(boost::posix_time::seconds(10));// std::cout << "timer canceled count is = " << cancelcnt << std::endl;// timer_.async_wait(boost::bind(&session::handle_timeout,this,// boost::asio::placeholders::error)); socket_.async_receive(boost::asio::buffer(data_, 1), boost::bind(&session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));//发起异步读操作，以便后面正常退出 } } else { std::cout << "error = " << error << " bytes_transferred = " << bytes_transferred << std::endl; this->handle_exit(); delete this;//这句不能放在handle_exit里面，否则问题多多，没找到好的解决方案 } } void handle_write(const boost::system::error_code& error) { if (!error) { std::cout << "handle_write ok/n"; this->handle_exit(); } else { std::cout << "handle_write error/n"; } return; } void handle_timeout(const boost::system::error_code& e) { if (e != boost::asio::error::operation_aborted) { std::cout << "timeout now./n"; this->handle_exit(); } else {//被取消 std::cout << "cancelled now./n"; } return; } void handle_exit() { std::cout << "enter handle_exit1./n"; if (!exit_flag_) { std::cout << "enter handle_exit2./n"; exit_flag_ = true; timer_.cancel(); socket_.close(); std::cout << "after socket close./n"; /* Any asynchronous send, receive or connect operations will be cancelled immediately, and will complete with the boost::asio::error::operation_aborted error */ //delete this; return; } else { return; } }private: tcp::socket socket_; boost::asio::deadline_timer timer_; bool exit_flag_; enum {header_lenght = 4, max_length = 1024 }; char data_[max_length];};class server{public: server(boost::asio::io_service& io_service, short port) : io_service_(io_service), acceptor_(io_service, tcp::endpoint(tcp::v4(), port)) { session* new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } void handle_accept(session* new_session, const boost::system::error_code& error) { if (!error) { new_session->start(); new_session = new session(io_service_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session, boost::asio::placeholders::error)); } else { delete new_session; } }private: boost::asio::io_service& io_service_; tcp::acceptor acceptor_;};int main(int argc, char* argv[]){ try { boost::asio::io_service io_service; server s(io_service, 9000); io_service.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "/n"; } return 0;} 

 

下面是python测试脚本：

import socket,sys,timehost = sys.argv[1]strPort = sys.argv[2]sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)port = int(strPort)try: sock.connect((host,port))except socket.gaierror,e: print "addr error:%s" % e sys.exit(1) except socket.error,e: print "connection error :%s" % e sys.exit(1) try: pack = 'hello world!' packheader = '%04d' % len(pack) print "header : %s" % packheader sock.sendall(packheader) sock.sendall(pack) time.sleep(10) sock.sendall("hello world from python2!") recvbuf = sock.recv(1024) print "recv data : %s " % recvbufexcept socket.error,e: print "send data error : %s" % e sys.exit(1) print "exit now" 

 

测试脚本中的内容可以灵活修改，用python写这个实在是方便，比起用C++来写，强多了。
      最后，欢迎大家到www.opensourceinsight.com交流哦，呵呵

 

本文转自：http://www.cppblog.com/true/archive/2008/07/20/56678.html

 

注：

一般来说,接收和发送时均应该使用asio::async_read/write，如果接收时协议无清晰格式，例如没有一个固定长度的header_len，则使用socket::async_read_some。